Fire alarm



Juhe 10, 1947.

J. w. TOUSIGNANT FIRE ALARM Filed Aug. 30, 1945 Patented June 10, 1947UNITED STATES PATENT OFFICE FIRE ALARM Joseph Wilfrid Tousignant,Plattsburg, N. Y. Application August 30, 1945, Serial N0. 613.633

6 Claims. 1 The present invention pertains to a novel fire alarm whereinthe alarm circuitis closed through the unequal expansion of a pair ofwires. The

- principal object of the invention is to provide a simple andinexpensive device of this character operating on the stated principle.

Another object is to provide such a device wherein expansion of thewires due to a rise in the climatic temperature does not sound thealarm.

In the accomplishment of these objects the device comprises a pair ofparallel wires, one of which is shielded in a perforated tube. Bothwires have one end connected to a lever mounted in the tube near one endthereof and their remaining ends fastened at relatively fixed points atthe remote end of the tube. The wires are joined intermediate their endsby a conducting clip passing through one of the apertures in the tube.The clip carries a contact finger cooperating with a normally spacedcontact finger disposed therebeneath and fastened on the tube butinsulated therefrom. The insulated finger is connected into the circuitof the alarm which also includes the clip and a portion of the externalwire. As stated, the circuit is normally open at the contact fingers.

On sudden rise of temperature, the external or exposed wire expands morrapidly than the wire shielded within the tube. Consequently theshielded wire is tensioned and pulls down the clip and its contactfinger engages the fixed finger, thereby completing the circuit. Duringslow temperature changes, however, the shielded Wire is heated throughthe apertures in the tube at substantially the same rate as the exposedwire. A spring drawing on the aforementioned lever maintains the wiresin a taut condition, with the result that there is no displacement ofthe clip and finger carried thereby.

The invention is fully disclosed by way of example in the followingdescription and in the accompanying drawings in which:

Figure 1 is a, longitudinal section of the device;

Figure 2 is a side elevation;

Figure 3 is a section on the line 33 of Figure 1;

Figure 4 is a detail perspective view, and

Figure 5 is a corresponding cross section.

Reference to these views will now be made by use of like characterswhich are employed to designate corresponding parts throughout.

In Figure 1 is shown a suitable support I, such as a ceiling, from whichthe device is supported by a, pairof brackets 2. Between the brackets ismounted a tube 3 having a series of apertures I for a purpose that willpresently by described. Near one end of the tube is mounted a U-shapedarm or lever 5 extending transversely of the tube, as shown in Figure 3,and having one of its legs 6 pivotally supported in the tube. The otherleg 1 is somewhat shorter and extends into one of the apertures '4. Athermally expansive wire 8 has'on'e end fastened to the swinging leg Iof the member 5 and its opposite end fastened at 9 to'the oppositebracket 2, the wire being disposed externally of the tube 3, as showninFigures l to 4.

' A similar wire 18 is disposed within the tube and also has one endfastened to the free or swinging leg 1 of the lever 5. In the oppositeend of the tube 3 is pivotally mounted a, bell crank lever I I to whichthe other end of the wire 10 is fastened. The tension of the wire can beadjusted by a set screw 12' threaded in the tube and bearing on'one legof the bell crank lever. At th opposite 'end of the tube, a coil spring13 has its ends attached respectively to the swinging leg 1 and to theadjacent bracket 2, drawing on the leg '1 to maintain the Wires in a.taut condition.

A clip l4 connects both wires '8 and I2 substantially at theirmid-points by passing through one of the apertures 4. A contact finger15 extends laterally from the clip externally of the tube 3. Adjacent tothe finger l5, anoth'er contact finger I6 is fastened to the tube 3 in aposition to lie perpendicular to the finger [5. The contact i6 isinsulated from the tube 3 and is spaced from the finger 45 in the normalposition of the device, as shown in Figure 2.

At a suitable location on the tube 3 are mount- 'ed two binding posts l1and I8 insulated from each other. The contact I8 is joined to the post Hby a, conductor l9. To the post 11 is also attached a conductor 20comprised in an alarm circuit. The other side of the circuit isrepresented by a conductor 22 fastened to the post l8 and grounded ifthe alarm device is also grounded.

In the operation of the device a gradual rise of temperature due toclimatic conditions does not affect the alarm circuit which is normallyopen. This is due to the fact that the Wire 10, although shielded by thetube 3, is heated at the same slow rate through the apertures 4 as theexposed wire 8 and, since the wires expand equally and the slack istaken up by the spring I3, the position of the clip l4 and the contactarm 5 is not changed. However, in a sudden rise of temperature due tofire, the wire 8 expands more rapidly than the wire l0. Consequently thewire 8 is pulled down by shielded wire l tensioned by spring [3 as shownin the dotted line position shown in Figure l, bringing the finger itinto contact with the finger IS. The alarm circuit includes the tube,which is not insulated from the post !8, and also the nearer bracket 2,the portion of the wire 8 between the bracket and the clip l4, and theclip itself. Consequently, the engagement of the contacts I5, l6 closesthe alarm circuit.

Although a specific embodiment of the invention has been illustrated anddescribed, it will be understood that various alterations in the detailsof construction may be made without departing from the scope of theinvention as indicated by the appended claims.

What I claim as my invention is:

1. A fire alarm comprising an apertured tube, a lever mounted near oneend of said tube, a wire having one end fastened to said lever and theother end fixed near the remote end of the tube, said wire beingdisposed externally of said tube, another wire disposed Within said tubeand having its ends fixed respectively to said lever and near the remoteend of said tube, a conductive clip joining said wires intermediatetheir ends and passing through one of the apertures of said tube, acontact finger extending from said clip, another contact finger mountedon said tube below the first finger and normally spaced therefrom.

2. A fire alarm comprising an apertured tube, a lever mounted near oneend of said tube, a wire having one end fastened to said lever and theother end fixed near the remote end of the tube, said wire beingdisposed externally of said tube, another wire disposed within said tubeand having its ends fixed respectively to said lever and near the remoteend of said tube, a conductive clip joining said wires intermediatetheir ends and passing through one of the apertures of said tube, acontact finger extending from said clip, another contact finger mountedon said tube below the first finger and normally spaced therefrom, and aspring bearing on said lever in the direction to tighten said wires.

3. A fire alarm comprising an apertured tube, r

a lever mounted near one end of said tube, a wire having one endfastened to said lever and the other end fixed near the remote end ofthe tube, said wire being disposed externally of said tube,

another wire disposed within said tube and having its ends fixedrespectively to said lever and near the remote end of said tube, aconductive clip joining said wires intermediate their ends and passingthrough one of the apertures of said tube, a contact finger extendingfrom said clip, another contact finger mounted on said tube below thefirst finger and normally spaced therefrom, a pair of binding postsmounted on said tube and insulated from each other, a conductor joiningthe second finger to one of said posts, and conductors attached to saidposts and adapted for connection to a current source and an alarm.

4. A fire alarm comprising an apertured tube, a lever mounted near oneend of said tube, a wire having one end fastened to said lever and theother end fixed near the remote end of the tube, said wire beingdisposed externally of said tube, another wire disposed within said tubeand having its ends fixed respectively to said lever and near the remoteend of said tube, a conductive clip joining said wires intermediatetheir ends and passing through one of the amrtures of said tube, acontract finger extending from said clip, another contact finger mountedon said tube below the first finger and normally spaced therefrom, aspring bearing on said lever in a direction to tighten said wires, apair of binding posts mounted on said tube and insulated from eachother, a conductor joining the second finger to one of said posts, andconductors attached to said posts and adapted for connection to acurrent source and an alarm.

5. A fire alarm comprising an apertured tube, U-shaped lever having oneleg pivot-ally mounted in said tube near an end thereof, a wire havingone end fastened to said lever and the other end fixed near the remoteend of the tube, said wire being disposed externally of said tube,another wire disposed within said tube and having its ends fixedrespectively to said lever and near the remote end of said tube, aconductive clip joining said wires intermediate their ends and passingthrough one of the apertures of said tube. a contact finger extendingfrom said clip, an other contact finger mounted on said tube below thefirst finger and normally spaced therefrom.

(i. A fire alann comprising an apertured tube, a U-shaped lover havingone leg pivotally mount ed in said tube near an end thereof, a wirehaving one end fastened to said lever and the other end fixed near theremote end of the tube, said wire being disposed externally of saidtube, an-

' other wire disposed within said tube and having its ends fixedrespectively to said lever and near the remote end of said tube, aconductive clip joining said wires intermediate their ends and passingthrough one of the apertures of said tube, a contact finger extendingfrom said clip, another contact finger mounted on said tube below thefirst finger and normally spaced therefrom, and a spring bearing on saidlever in a direction to tighten said wires.

JOSEPH W ILFRID TOUSIGNANT.

REFERENCES CITED The following references are of record in the file ofthis patent:

FOREIGN PATENTS Number Country Date 1,145 Australia Mar. 25, 1926

